This invention relates to a composition for protecting a plant from a disease and a using method thereof. More particularly, it relates to a composition for protecting a plant from a disease that induces production of a phytoalexin by application to a plant and suppresses pathogenic plant bacteria, and further a method of applying said composition to a plant in order to induce production of a phytoalexin and suppress various pathogenic plant bacteria resulting in protection of a disease of plant.
The present inventors have already found out that treatment of methionine to a rice plant is capable of inducing production of a phytoalexin that donates resistance to various diseases (Japanese Patent Application H09-44206). Treatment of methionine to a rice plant induces accumulation of phytoalexins such as Sakuranetin and Momilactone, and resultantly donates resistance to rice blight (Pyricularia oryzae) that is a representative disease of rice plants. However, the effect of using methionine alone has proved to be insufficient and occasionally led to an inability to exhibit a desired effect.
The primary object of the present invention is to provide a composition for protecting a plant from a disease that induces production of a phytoalexin by application to a plant and suppresses plant bacteria more effectively than using methionine alone, and can be used throughout the year. The secondary object of the present invention is to provide a method of applying said protecting composition to a plant in order to induce production of a phytoalexin, suppress plant bacteria, and resultantly protect a plant from plant diseases.
The present inventors found that combined use of sulfur-containing amino acids and D-glucose, not single use of sulfur-containing amino acids such as methionine, exhibits a superior effect for suppressing not only plant diseases including rice blight (Pyricularia oryzae) at the aboveground position, but also soil diseases such as damping-off, which led to the exhibition of much more effective protecting ability for plant diseases, and accomplished the present invention.
The present invention provides a composition for protecting a plant from a disease that induces production of a phytoalexin by application to a plant for the purpose of suppressing pathogenic plant bacteria, that is, a composition characterized by containing at least one amino acid selected from the group of sulfur-containing amino acids comprising methionine, cycteine, and cystine, and D-glucose in a mixed form. Preferably said composition contains methionine as a sulfur-containing amino acid. Likewise, the mixed ratio by weight of a sulfur-containing amino acid to D-glucose in said protecting composition is preferably within the range of 1:(50-0.001).
Furthermore, the present invention provides a method of using said composition for protecting a plant from a disease, characterized by spraying said composition on the aboveground part of a plant either undiluted or after dilution with water by 1-100,000 times. More particularly, the present invention provides a method of using said composition for protecting a plant from a disease characterized either by mixing said composition directly with soil or by irrigating said composition after dilution with water by 1-1,000,000 times.
Furthermore, the present invention provides a method of using said composition for protecting a plant from a disease characterized by powder-coating plant seeds with said composition either directly or after supporting on a carrier. Furthermore, the present invention provides a method of using said composition for protecting a plant from a disease characterized by impregnating plant seeds with aqueous solution of said composition diluted by 10-1,000,000 times
The illustrative embodiments of the invention will be described with particularity hereafter.
FIG. 1 illustrates the dynamic protection mechanism of plant against plant bacteria.
In the present invention the term xe2x80x9csulfur-containing amino acidxe2x80x9d refers to at least one kind of sulfur-containing amino acids selected from the group comprised of methionine, cysteine, and cystine. These amino acids are not particularly limited in any manner. For example, any of L-methionine, DL-methionine, D-methionine, L-cysteine, DL-cysteine, D-cysteine, L-cystine, DL-cystine, L-cystine may be used. DL-methionine is most preferred in view of its lowest cost. The employed form is not limited in any manner: it may be a powder, an aqueous solution, or a dispersion of a sulfur-containing amino acid dispersed in a dispersion medium. In case amino acids are used as an aqueous solution, however, methionine or cysteine is preferred as the sulfur-containing amino acid since cystine is hardly soluble in water. The amount of sulfur-containing amino acids employed depends on the species of plant and the method of application, and may be determined accordingly.
D-glucose that is employed in the present invention is not particularly limited in any manner. Its employed amount may be determined appropriately depending on the species of plant and the method of application. The employed form is not limited in any manner: it may be a powder, an aqueous solution, or a dispersion of D-glucose dispersed in a dispersion medium. Depending on the production method, D-glucose may contain a part of other monosaccharides, oligosaccharides such as sucrose, maltose, and lactose, polysaccharides such as starch, cellulose, dextran, laminaran, and glycogen, as well as various glycosides. It can be used without difficulty unless the content of these compounds is within an area in which the effect of the present invention is not hurt.
The mixed ratio of sulfur-containing amino acids to D-glucose prepared for the purpose of the present invention is generally within the range of 1 to 50-0.001 by weight, preferably within the range of 1 to 10-0.01, most preferably 1 to 1-0.1. A ratio of sulfur-containing amino acids to D-glucose larger than 50 hampers the effect of sulfur-containing amino acids. A ratio of sulfur-containing amino acids to D-glucose less than 0.001 exhibits an insignificant effect similar to single use sulfur-containing amino acid, and thus is not preferred.
With regard to the amount of application for said composition according to the present invention, it is generally within the range of 10-30,000 g per 10 ares, preferably within the range of 50-5,000 g per 10 ares, more preferably within the range of 100-1,000 g. An amount of less than 1 g leads to an insignificant effect, and thus is not preferred. An amount of larger than 30,000 g exhibits unfavorable side effects such as yellowing of foliage and growth inhibition of roots, and thus is not preferred.
With regard to the method of application of said composition for protecting a plant from a disease at the aboveground part of a plant according to the present invention, the composition may be sprayed either undiluted or diluted with water by 1-100,000 times, preferably 1-10,000 times, most preferably 500-2,000 times. Dilution of more than 100,000 times leads to an insignificant effect. It is possible to employ said composition for protecting a plant from a disease according to the present invention in the form of direct mixing with soil or irrigating after dilution with water. In a latter case, it may be employed generally at dilution of 1-1,000,000 times with water, preferably at 1-100,000 times, most preferably at 500-10,000 times. Dilution of more than 1,000,000 times with water leads to an insignificant effect.
When the method of seed impregnation is adopted for said composition for protecting a plant from a disease according to the present invention, it may be employed at dilution of generally 10-1,000,000 times with water, preferably at 10-1,000,000 times, most preferably at 10-10,000 times. Dilution of less than 10 times might yield a chance of incomplete dissolution of the effective components, while at dilution of more than 1,000,000 times the necessary amount of the effective components might not be conveyed to the impregnated seeds within a prescribed time.
Concerning the application interval of said composition for protecting a plant from a disease according to the present invention, It is preferred to be applied every 3-14 days periodically in general. However, it is also possible to apply it every day or with a long interval depending on the stage of growth, the species of plant, or the situation of growth.
With regard to the amount of application, It is generally within the range of 10-10,000 ml per square meter. An amount of less than 10 ml exhibits an insignificant effect, and thus is not preferred. An amount of more than 10,000 ml frequently exhibits a side effect of excess damp to seedlings, and thus is not preferred. It may be applied preferably within the range of 100-5,000 ml per square meters, more preferably within the range of 300-2,000 ml. In a case of spraying in a main farm, it may be sprayed generally within the range of 1-500 L per 10 ares, preferably within the range of 10-300 L, more favorably within the range of 50-200 L. In a case of irrigating in a main farm, it may be irrigated generally within the range of 10-30,000 L per 10 ares, preferably within the range of 100-15,000 L, more favorably within the range of 1,000-10,000 L.
In a most preferred application method for the seedling period, it is applied at 500 ml per square meters in an irrigating form every five days starting from the period of 1.5 blades. After the seedlings are transplanted to a main farm, it may be irrigated preferably every ten days at 1,500 L. It is possible to combine agro-active ingredients such as antibacterial agents and insecticides, fertilizers, growth modifiers, viscosity modifiers, and surfactants, which are all noted for absence of sulfur-containing amino acids and D-glucose, with said composition for protecting a plant from a disease according to the present invention within a range in which the effect of the present invention is not hurt.
The agro-active ingredients employed in the present invention are not particularly limited. They may be used singly or in combination with two or more species at optional ratio. The following compounds are given as only examples. Note that the following names of agro-active ingredients are based on the general description in the Agrochemicals Handbook (published by Japanese Association of Plant Disease Prevention, 1989).
Examples of herbicides included in the present invention are; 2,4-D, MCP, MCPB, CNP, MCC, DCPA, CAN, Phenothiol, Cromeprop, Naproanilid, Crometoxinil, Benthiocarb, Biphenox, Esprocalp, Morinate, Dimepirate, Butachlor, Prethirachlor, Bromobutid, Mephenaset, Dymron, Bensulfronmethyl, Symmetrin, Brometrin, Dimethametrin, Bentazon, Oxadiazon, Pyrazorate, Pyrazoxifen, Benzofenap, Trifluralin, and Biperofos.
Examples of insecticides included in the present invention are; BRP, CVMP, PMP, PAP, DEP, EPN, NAC, MTMC, MIPC, BPMC, PHC, MPMC, XMC, MPP, MEP, Pyrimifosmethyl, Diazinon, Isoxathion, Pyridafenthion, Chlorpyrifosmethyl, Pamidthion, Marathon, Dimethoate, Ethylthiometon, Monochlotofos, Probafos, Bendaioaclp, Thiodicalp, Cycliprotolin, Ethofenprox, Kaltap, Thiocyclum, Bensultap, and Buprofezin.
Examples of antibacterial agents included in the present invention are; basic cupric sulfate, basic cupric chloride, cupric hydroxide, organic sulfuric salts of nickel, Thiraum, Captan, TPN, Furacide, IBP, EDDP, Thiofanatemethyl, Benomil, Iprodion, Mepronil, Furutranil, Teflofratam, Bencyclon, Metharaxil, Triflumizol, Brastcyzin-S, Kasugamycin, Polyoxin, VaridamycinA, Oxytetracycsin, Hydroxyisoxazol, methasulfocalp, MAF, MAEE, Benthiazol, Fenazinoxid, Dichlomezin, Propenazol, Isoprothioran, tricyclazol, pyrokiron, Oxonic Acid, and Guazatin.
Furthermore, it is possible to add plant growth modifiers such as Inavenfid, oxyethylenedokosanol, nicotinic acid amide, and benzylaminopurine.
The fertilizer component employed in the present invention is not particularly limited. Examples of fertilizers included in the present invention are; compost, barnyard manure, cattle excreta, human excreta, vegetation ash, tree ash, rice straw, wheat straw, rice husk, rice sugar, wheat sugar, pea pod, nitrogen fertilizers, phosphate fertilizers, potassium fertilizers, composite fertilizers, lime fertilizers, silicate fertilizers, magnesia fertilizers, manganese fertilizers, borate fertilizers, trace mineral compound fertilizers, organic fertilizers, fish refuse, droppings of poultry and cattle, processed dung of poultry and cattle, their burned ash, drain fertilizers, lime byproducts at sugar manufacturing, scraps of revolving furnace, shell lime powder, waste of agricultural products, refuse in food industry, waste of fermentation industry, dregs in fermentation, waste of textile industry, dregs in marine products industry, sludge of drainage, compost from urban trash, bone ash, etc. These fertilizer components may be employed singly or in combination with two or more species mixed at optional ratio. In addition to the above products, it is possible to combine soil modifiers such as zeolite, bentonite, vermiculite, peat, perlite, humic acid-based materials, charcoal, polyethyleneimine-based materials, and PVA-based materials.
Examples of surfactants in the present invention are; anionic surfactants including; alkylsulfosuccinic acid salts, condensated phosphate acid salts, alkylbenzenesulfonic acid salts such as dodecylbenzenesulfonic acid sodium salt, alkylnaphthalenesulfonic acid salts, formalin condensates of naphthalenesulfonic acid salts, ligninsulfonic acid salts, polycarboxylic acid salts, alkylethersulfuric acid salts, polyoxyethylene-alkylarylphenylether-sulfuric acid salts, polyoxyethylene-alkylarylether-sulfuric acid salts, polyoxyethylene-alkylaryl-sulfuric acid salts, polyoxyethylene-alkylarylether-sulfate ester salts, polyoxyethylene-alkylarylether-acetate ester-sulfuric acid salts. The salt form includes alkali-metal salts, ammonium salts, and amine salts.
Furthermore, examples of surfactants in the present invention include; nonionic surfactants such as; polyoxyethylene-alkylether, polyoxyethylene-alkylarylether, polyoxyethylene-alkylarylphenylether, polyoxyethylene-styrylphenylether, polyoxyethylene-alkyl ester, sorbitan-alkyl-ester, polyoxyethylene-sorbitanalkyl-ester, and polyoxyethylene-polyoxypropyleneglycol. It is possible to combine cationic surfactants with amphoteric ionic surfactants depending on the necessity. These surfactants may be employed singly or in combination with two or more species mixed at optional ratio.
It is thus possible to improve the resistance of a plant to a pathogenic disease by application (irrigating, etc. on a plant) of said composition for protecting a plant from a disease according to the present invention, which contains a mixture of sulfur-containing amino acids such as methionine and D-glucose, and by resultant acceleration in the production of a phytoalexin that is an antibacterial substance produced in the biosynthesis by plant itself.